Practically all current computer systems have one or more realtime clocks. Realtime clocks are used particularly to continually update a system time for the computer system. Furthermore, known realtime clocks often have what is known as an alarm function, which can be used to initiate interrupt requests under time control. The interrupt requests initiated by a realtime clock can be intercepted by another hardware or software component, particularly a BIOS program or an operating system executed by a processor in the computer system, and used to initiate the execution of user-controlled processes.
One problem with the known computer systems is that it is not possible for programming of the realtime clocks to be successfully checked in every state of the computer system. Particularly when the computer is in a completely switched-off state, a relevant interrupt request is either not initiated by the realtime clock chip or not evaluated by another hardware or software component. In this case, tasks prescribed by the user are sometimes not executed.
If the computer system is in what is known as a standby state, on the other hand, it is possible to initiate and evaluate such interrupt requests. In that case, however, there is the disadvantage that the computer system in the standby state usually needs to continue to be supplied with an operating voltage, with the result that electrical power is consumed independently of the actual use of the computer system. In the case of mains-operated computer systems, that results in a reduction in efficiency, and in the case of battery-operated systems, it results in premature exhaustion of the battery cells used.
It could therefore be helpful to provide a computer system, a method of programming a realtime clock and a computer program product which wholly or partially overcome the aforementioned disadvantages, and to provide a computer system and a method of operation thereof which allow time-controlled events to be monitored without requiring the computer system to be constantly supplied with power.